The function of the amniotic cavity is

In human beings,usually the gestation period lasts for about . . . . . . days,from the beginning of the last menstrual cycle.

Select the mismatched pair:
$A$. First month of pregnancy - Formation of heart
$B$. Second month of pregnancy - Movement of foetus
$C$. Third month of pregnancy - Formation of most of the major organ systems
$D$. Sixth month of pregnancy - Eye lids separate and eye lashes are formed

$A$ phenomenon of embryonic induction was first described in amphibia by

Which structure differentiates the gastrula from the blastula?

Major features of embryonic development at various months of pregnancy are given below. Choose the correct option for the correct sequential events.
$(i)$ The first movements of the foetus
$(II)$ The foetus develops limbs and digits
$(III)$ The embryo's heart is formed
$(IV)$ The body is covered with fine hairs